Pug-mill knife



F. O. RUSH.

PUG MILL KNIFE.

APPLICATION FILED OCT-15. 1917.

1,347,876, Patented July 27, 1920.

gag/am k v whi UNITED STATES PATENT OFFICE.

FRED O. RUSH, OF NEW CASTLE, DELAVARE, ASSIGNOR T0 AMERICAN MANGANESE STEEL COMPANY, .OF CHICAGO, ILLINOIS, A CORPORATION OF PUG-MILL KNIFE.

Specification of Letters Patent.

Patented July 27, 1920.

7 Application filed. October 15, '1917. Serial No. 196,688.

To all whom it may concern: 7 Be it known that I, FRED O. RUSH, a citizen of the United'States, residing at New Castle, in the county of New Castle and State of Delaware, have invented certain new and useful Improvements in Pug-Mill Knives, of which the following is a specification.

My invention refers to pug mills and particularly to the type of mill having a rotary shaft on which aremounted a series of knife blades for the purpose of disintegrating the material in said mill. My invention has to do with a particular form of knife blade for use in a mill of the character described.

In pug mills used for the purpose of acting on mud, clay and the like, it has been the custom to employ knives mounted on arotating shaft which knives are placed at an angle to the direction of rotation so as to force the material in the mill toward thev exit. In some instances it has been custom ary to mount knives or blades on the interior of the mill in staggered relation to the rotating knives. Experience has shown that whenever in the use of a mill of this sort an obstruction is encountered'by the rotating "knives, the knife blade is very often broken off and" thus becomes a menace in stallation of a new one, a costly proceeding;

The primary object of my invention is to provide anovel knife so arranged on the shaft as to move in acircular direction with the blade being set at an angle to the direction of rotation and to overcome the objections experienced in the present day type ofknife. i

Another object is'to provide a knife so connected to the shaft .by, a safety member that when an obstacle is encountered in op eration, a portion of the fastening means will give way thus permitting the blade to swing out of engagement with the obstacle without breaking from the shaftattaching portion and without damaging the apparatus. Also inpermitting repairs by the installing of another safety member all of which 'may-be done without harming the knife blade in any degree and without removing the knife .from the shaft.

Also when tion without endangering the other knives or mill lining and which may be put into service by means of the installationof an inexpensive bolt, or the like. Y

These and other objects will be apparent from the drawings, wherein:

Figure-1 is an elevation of the preferred form of my knife as mounted on a shaft, the shaft being shown in section.

2 is an end view of Fig. 1. j

Fig. 3 is a rear View of the preferred form of knife, and v Fig. 4% shows in section two forms of shanks.

Shaft 5 is the usual shaft which is employed in mills of this character and may be mounted either vertically or horizontally. Attached to the'shaft are a series of blades or knives and sometimes a series of blades or knives are secured to theinner lining of the mill in staggered relation to the blades on the shaft. known to those skilled in the art, I consider it necessary herein to show only "a single knife as it is understood that several knives similar to the one shown are employed.

The novelty of my invention lies in the employment of a shank portion 6 and a separable blade 7, both of which may be castings and preferably of alloy steel such as manganese'steel, the shank 6 having an elongated member or shaft 8 for insertion in an appropriately arranged opening in the/shaft 5. If desirable the member 8 may be truly I circular in section and rovided with a keyway as shown at 9 in *ig. 2. I have preferred to cast the key integral with the body member 8. A yet further modification would bethe employment'of the member 8 slightly flattened on one portion toengage a correspondingly flattened portion of the opening 10 in the shaft 5. The shank 6 is cast with an enlarged head member 11 having two As this construction is well 5 the blade 7 to the head 11 of the shank porapertures 12 and 13 therein, the aperture 12 being larger in diameter than that of 13, the purpose of which will be explained later.

The rear portion of the head member 11 is' tion 6 apertures are provided therein for registering with the apertures12 and 13 in the head 11. Bolts 17 and 18 are inserted in said registering apertures and drawn 7 tight by .the'usual nuts. In the forward 7 operation of the mill.

stopped the blade may be brought into ophole 13 Iprefer to employ a bolt 'or safety member 18 that is smaller in diameter than the bolt 17. The end of the wedge 7 adja cent the shaft 5 when mounted on the head 11 is spaced therefrom and is curved slightly as shown by dotted lines in Fig. 1.] I prefer to arrange the bolts 17, 18 at substantially the same distance from the center or axis of the mill'shaft 5 so that the strain 011 the bolts will be more evenly divided.v

It will be observed that the shank member 6 may be formed of 'cast metal and inserted in the aperture 10 of the shaft 5 without the necessity of having to cut away any metal to bring the member 8 to the proper size and shape for interfitting with said aperture 10. By forming the key integral with the member 8' ormaking the member 8 withlthe flattened surface as shown in B in: Fig. 4, it is' possible to make a shank that requires practically no machining to make it adaptable for use. 7

In the operation of the device, blade 7 is mounted onthe head 11' by the bolts 12'and 18 and'rotated with the shaft 5. When an obstacle is encountered by the'cutting edge of the knife if it is such an obstacle which under ordinary circumstances would break the blade, it will break the safety member or bolt 13, thus causing the blade 7 to swing about the pivot and out of the way of the obstacle, the' blade, being swung back until its curved rear edge 15 rests against the shaft 5. It will thus be observed that it is possible to continue the operation of the mill without removal of the blade 7 from the mill and without damage beingdone to any of the blades on the shaft or to those mounted on the interior of the lining of the mill,

7 or evendoing any damage whatsoever to the lining of the mill itselfand still be possible to have the effectiveness of the blade in the When the millis the registering apertures 13;

erative position very easily by swinging it back in the position of the full lines in ig 1, and inserting another -bolt 18 .through it will be noted that when the breakable or smaller --bolt 13 is in position, the blade will move Theblade will still perform its function in ,the mill, but 7 will be in a slightly different or. following relation to the shaft 5 and the other blades. In no event, however, will it become in operative or loosened from .the portion 11.

It will be observed that Ihave provided a novel pug mill knife which. is provided with a safety member to enable the knife to'be swung out of operative'position without becoming disconnected from its shaft attachingshank, thus moving it into a po-' sition where no damage will: bejdone .to the other knives in the mill nor {to the lining thereof and which will permit of'a quick replacement position by the installation of a small bolt;

I donot wish to liinitfmy invention to the exact form shown and described asI am'aware that such a device is susceptible of d fica i n an nel v mod a n I sc oIfpe .of my invention. e I

claim:

onsider as coming within the spirit and 1. A pug mill knife comprisin ,com-

bination a blade and a separate sl lan k, said shank having an irregular-integrally formed portion for nonrotatively mounting said shank in the mill shaft, and means ncluding a lura ity f memb rs a ra g a u stantially the same distance from the axis of the shaft for securing the blade to the shank. V 2. A piug mill knife comprising in combination a blade and a separate shank, said shank havinga portion integrally formed therewith for nonnotatively mounting said shank in the mill shaft, the shank having a portionmade to,. conform to and abut part of some of the strain from the shankto the shaft, and means for securingthe blade to the shank.

shaft, and a blade secured to said head.

member at a plurality pf points, the securthe surface of the whereby to remove ing means being inserted near the lower end of blade.

4;. A pug mill knife including in combina- 7 tion a blade and a separate attaching'member, said attaching member having a shank irregular in cross section adapted to engage a similarly shaped aperture in the mill shaft, said attaching member having also an enlarged head portion adapted to abut said mill shaft, and means for attaching said blade to said enlarged portion at a plurality of points.

5. A pug mill knife including in combination a blade and a separate attaching member, said attaching member having a shank irregular in cross section adapted to engage a similarly shaped aperture in the mill shaft, said attaching member having also an enlarged head portion adapted to abut said mill shaft, and means for attaching said blade to said enlarged portion at a plurality of points, near the end of the blade.

6. A pug mill knife including in combination a blade and a separate attaching member, said attaching member having a shank portion of irregular cross section adapted to engage a similarly shaped aperture in the mill shaft, and means for securing said blade to said attaching member at a plurality of points, the attaching member nearer the shank being Weaker than the member farther from the shank.

Signed at New Castle, State of Delaware this7 fourteenth day of September, A. D. 191

FRED o. RUSH. 

